Method and system for driving an active matrix display circuit
A method and system for driving an active matrix display is provided. The system includes a drive circuit for a pixel having a light emitting device. The drive circuit includes a drive transistor for driving the light emitting device. The system includes a mechanism for adjusting the gate voltage of the drive transistor.
1. A display system, comprising:
a pixel circuit for operating a light emitting device to emit light according to programming information, the pixel circuit including:
a drive transistor connected in series to the light emitting device, the drive transistor including a gate terminal, a first terminal and a second terminal,
a first switch transistor including a gate terminal, a first terminal and a second terminal, the gate terminal of the first switch transistor being connected to a select line for operating the first switch transistor, the first terminal of the first switch transistor being connected to a data line providing a programming voltage according to the programming information during a programming cycle, the second terminal of the first switch transistor being connected to the gate terminal of the drive transistor, and
a circuit for adjusting the gate voltage of the drive transistor by at least partially discharging the voltage on the gate terminal of the drive transistor through a discharge component having a resistance that varies as the pixel circuit ages, and
a controller for operating the data line and the select line to drive the pixel circuit such that:
the programming voltage is provided on the data line during the programming cycle to thereby charge the gate terminal of the drive transistor with the programming voltage via the first switch transistor, and
the programming voltage is at least partially discharged through the discharge component during a frame that includes a compensation cycle following the programming cycle while the first switch transistor is turned off, and
the pixel circuit is driven to emit light during a driving cycle according to the voltage remaining on the gate terminal of the drive transistor following the at least partial discharge.
2. A display system, comprising:
a pixel circuit for operating a light emitting device to emit light according to programming information, the pixel circuit including:
a drive transistor connected in series to the light emitting device, the drive transistor including a gate terminal, a first terminal and a second terminal,
a first switch transistor including a gate terminal, a first terminal and a second terminal, the gate terminal of the first switch transistor being connected to a select line for operating the first switch transistor, the first terminal of the first switch transistor being connected to a data line providing a programming voltage according to the programming information during a programming cycle, the second terminal of the first switch transistor being connected to the gate terminal of the drive transistor, and
a circuit for adjusting the gate voltage of the drive transistor by at least partially discharging the voltage on the gate terminal of the drive transistor through a discharge component having a resistance that varies as the pixel circuit ages, and
a controller for operating the data line and the select line to drive the pixel circuit such that:
the programming voltage is provided on the data line during the programming cycle to thereby charge the gate terminal of the drive transistor with the programming voltage via the first switch transistor,
the pixel circuit is driven during a frame that includes the programming cycle to emit light during a driving cycle according to the current through the drive transistor,
a characteristic of the discharge component is extracted during an extraction cycle following the programming cycle during the frame, and
a luminance degradation of the pixel is compensated, using the extracted characteristic, by calibrating a programming voltage that is applied in another frame.